helper script for netmaker, to inject netmaker peers into /etc/hosts

netclient2hosts.py

#!/usr/bin/python3
'''
script to merge netmaker clients from all bound networks into the
local system's hosts file.
'''

import subprocess
import json

HOST_FILE = '/etc/hosts'
NETCLIENT = '/usr/local/bin/netclient'

def get_netclient():
    ''' runs the netclient list command and creates a dict '''
    client_config = {}
    process = subprocess.Popen([NETCLIENT, 'list'],
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE)
    stdout, stderr = process.communicate()
    if stderr:
        print(stderr)
    else:
        output = stdout.decode("utf-8")
        nc_config = json.loads(output)
        for item in nc_config["networks"]:
            for client in item["peers"]:
                client_config[client["private_ipv4"]] = client["name"]
    return client_config

def write_config(netclient_config):
    ''' write new netclient data to hosts file '''
    if isinstance(netclient_config, dict):
        # clear netclient host data
        host_config = open(HOST_FILE, 'r')
        host_lines = host_config.readlines()
        host_config.close()
        try:
            # check for previous config
            start = host_lines.index('############ netclient_hosts ############\n')
            try:
                finish = host_lines.index('#########################################')
            except ValueError:
                finish = host_lines.index('#########################################\n') + 1
            del host_lines[start:finish]
            clean_config = host_lines
        except ValueError:
            clean_config = host_lines

        # cleanup end of file spacing
        cleaned = False
        while cleaned is False:
            if clean_config[-1] == ('\n'):
                del clean_config[-1]
            else:
                cleaned = True

        # append netclient current config
        client_data = ['\n', '############ netclient_hosts ############\n']
        for key, val in netclient_config.items():
            line = "%s   %s\n" % (key, val)
            client_data.append(line)
        client_data.append('#########################################\n')
        new_config = clean_config + client_data

        # write changes
        host_config = open(HOST_FILE, 'w')
        host_config.writelines(new_config)
        host_config.close()

new_clients = get_netclient()
write_config(new_clients)